Transverse natural frequencies and flow-induced vibrations of double bellows expansion joints
Transverse natural frequencies and flow-induced vibrations of double bellows expansion joints
复制标题
双波纹管膨胀节的横向固有频率和流致振动
DOI：
10.1006/jfls.1999.0215
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
D. Weaver
中科院分区：
文献类型：
--
作者：
V. Jakubauskas;D. Weaver
本文研究了充液双波纹管膨胀节的横向振动问题。波纹管被建模为一个Ekshenko梁，流体附加质量包括旋转惯性和波纹管的卷积变形效应。固有频率的瑞利商，并考虑连接波纹管单元的管道的横向和摇摆模式。前六个模式的理论预测进行了比较，在静止的空气和水的实验和协议是非常好的。然后研究了双波纹管的流致振动，波纹管位于直管段和90°弯头的下游。Strouhal数计算每个流激发模式共振。波纹管的固有频率不受流动流体的影响，但直接上游弯管的存在大大降低了激发共振所需的流速。
This paper considers the transverse vibrations of fluid-filled double-bellows expansion joints. The bellows are modelled as a Timoshenko beam, and the fluid added mass includes rotary inertia and bellows convolution distortion effects. The natural frequencies are given in terms of a Rayleigh quotient, and both lateral and rocking modes of the pipe connecting the bellows units are considered. The theoretical predictions for the first six modes are compared with experiments in still air and water and the agreement is found to be very good. The flow-induced vibrations of the double bellows are then studied with the bellows downstream of a straight section of pipe and a 90° elbow. Strouhal numbers are computed for each of the flow-excited mode resonances. The bellows natural frequencies are not affected by the flowing fluid but the presence of an immediate upstream elbow substantially reduces the flow velocity required to excite resonance.